Production of structural timepiece components by electroforming makes it possible to obtain perfect geometry, a good surface state and a flawless appearance, using a small amount of expensive material, due to the small thickness of the parts produced. In the case of external components (cases, links, bezels, and suchlike), the parts obtained are hollow shells, whose mechanical properties must be approved according to the application.
The resistance of such shells is related to their geometry, and it is clear that to obtain a reasonably rigid shell, including ribs, or horn-shaped stiffening members, it is necessary first to machine a substrate to be used as a core, which is of quite complex shape and consequently expensive. Otherwise, it is difficult for a non-stiffened shell to withstand assembly to other components, such as a back cover, horns, a bracelet or strap or other element, and is liable, at best, to be deformed to an extent that is detrimental to the sealing of the timepiece in which the shell will be incorporated, or at worst to tear or crack.
CH Patent No 692531 in the name of Maire discloses a watch case formed of a thin metallic wall, of substantially constant thickness. The wall defines, in a part forming a bezel, a cylindrical surface which circumscribes an upper opening closed by a crystal secured by a gasket to the wall, and an open groove on a housing for receiving a movement. A retaining ring is removably fixed inside the groove.
EP Patent Application No 0762240A1 in the name of Fabrique d′ébauches de Sonceboz SA discloses a container including a hollow case and a casing ring, with an electroformed case middle having thin precious metal walls, defining a concave inner face. The casing ring, which is made of cheaper material, is inserted into the case middle from the side of a back cover removably assembled to the case middle, separated by a recess from the inner face, and is held therein by compression between upper and lower bearing surfaces respectively defined by a portion of the inner face of the back cover, and by a portion of the inner face of the case middle EP Patent Application No 0716360A1 in the name of Fabrique d′ébauches de Sonceboz SA discloses a similar watch case wherein the upper and lower bearing surfaces are parallel to the back cover and wherein the casing ring may have a variable thickness during insertion or in the operating position, under the effect of mechanical means or of its own elasticity.
EP Patent Application No 1742120 A2 in the name of Richemont discloses a watch including a case with a fixed part and a movable part which includes a case middle and a movement, both pivotally mounted on the fixed part along a pivot axis by pivots to perform a tilting motion of the movable part in two opposite directions, achieved by pressure on one portion of the movable part. At least one activating mechanism cooperates with the fixed and movable parts to convert their relative tilting into an action on a control member accessible from the exterior of the movement and intended to activate at least one function.